I'm thinking about exploring aerodynamics for my E46. I think I understand how I want to mount a plywood front splitter...bolt it to the frame rail in the back and then use some struts to hold it up in the front. Use some hardware and elongated holes on the bottom on my front lip so I can adjust the lip to stick out less or more.

Now my question is what qualifies a rear wing as more or less functional? Is it the height relative to the rear decklid or roofline? Width? Angle?

The height of the wing (relative to the roof), chord length, width, and profile all matter. Go with a proven wing like the Bimmerworld wing or Brooks wing. APR GTC300 works well too, and is the cheapest. You don't just want downforce, you want to minimize added drag. And all of those wings are good at that.

The angle of attack is adjustable in any decent wing and you can adjust and see how you like it. More AOA is more drag and more downforce, up to the point of stall. I ran a Brooks wing and liked it and Brooks provides great support for club racers.

Make sure your splitter is more or less sealed to the bumper, and 3-4+" out from the front. The limiting factor in aero on production based cars is always the front.

Thanks for the info, that helped. What do you think about these wings? I'm not looking for something super awesome, CF, and/or ingenious. Something simple that provides some more downforce.

On my E46 330 Mtech bumper, I'll just throw on a strass lip as a riser and then bolt on my plywood splitter

The LTW style wing you linked is one of the worst profiles as far as downforce/drag ratio. If you want something cheaper that still provides good downforce look at APR stuff. The LTW wing was made to fit very strict series guidelines (had to fit in car's shadow or something IIRC), and is inefficient. The E36 guys that run them run them for looks more than anything.

Go for Bimmerworld or Brooks if you can afford it. Go for APR or something similar if you want less pricey hardware. I wouldn't recommend anything below APR price for a real functional wing. I ran the Brooks for 2 years and it rocked. At a low AOA it had very noticeable downforce and I had the same straightaway speeds due to slightly higher exit speed onto the straight and the slight added drag netting out.

Thanks for the info, that helped. What do you think about these wings? I'm not looking for something super awesome, CF, and/or ingenious. Something simple that provides some more downforce.

On my E46 330 Mtech bumper, I'll just throw on a strass lip as a riser and then bolt on my plywood splitter

The LTW style wing you linked is one of the worst profiles as far as downforce/drag ratio. If you want something cheaper that still provides good downforce look at APR stuff. The LTW wing was made to fit very strict series guidelines (had to fit in car's shadow or something IIRC), and is inefficient. The E36 guys that run them run them for looks more than anything.

Go for Bimmerworld or Brooks if you can afford it. Go for APR or something similar if you want less pricey hardware. I wouldn't recommend anything below APR price for a real functional wing. I ran the Brooks for 2 years and it rocked. At a low AOA it had very noticeable downforce and I had the same straightaway speeds due to slightly higher exit speed onto the straight and the slight added drag netting out.

+1
I ran a PTG copy MAShaw CF rear spoiler for years on my former track car and the drag was like a boat anchor at high speed (like back straight at WGI). Newer aero foil rear spoilers or a smaller TMS E46m3 spoiler would be great ways to go.
GL

Would the M3 GTS wing be somewhat decent in providing some rear down force?

Not really. It is way too small. If you're going to go for a wing do it right, APR or Bimmerworld/Brooks. I'd say the GTS wing provides "some" downforce, but it would be a fraction of what a real race wing can provide. Your best low-cost bet is APR.

I don't have a wing on my E92 yet, but if/when I do it is going to be for sure either Bimmerworld or Brooks. Proven aerofoil designs and sturdy mounts.

OK, thanks. I'm trying to find something that doesn't look totally embarassing since I still plan to drive it on the street. Looks like modest aero is just a waste and need to go 100% racecar.

Thanks!

No problem. Also bear in mind that effective front aero is likely not going to be street friendly at all. Low splitters that stick out several inches don't work so well on driveways and less than optimally paved surfaces. I'll probably eventually bite the bullet and put a wing on the E92, and just ignore the negative views of random street people.

There was a guy at VIR in his GTR with an automatically adjustable rear wing. Read the car speed off the OBD port, had a computer with a hydraulic actuator that read the G forces and adjusted the AOA in realtime.

Aerobraking on deceleration, maximum downforce on high speed sweepers and drag reduction on the straights.

There was a guy at VIR in his GTR with an automatically adjustable rear wing. Read the car speed off the OBF port, had a computer with a hydraulic actuator that read the G forces and adjusted the AOA in realtime.

Aerobraking on deceleration, maximum downforce on high speed sweepers and drag reduction on the straights.

Now that was a wing...

Ive seen some thing like that online its pretty awesome but some major $$$$$

Well in fairness that GTR was decked out like a Christmas tree, had every imaginable performance mod. Power, brakes, suspension, wheels, CF everything, a small computer inside for on the spot tuning etc.

When you get to that level, I guess the only other thing left to do is an $8000 wing.

Well in fairness that GTR was decked out like a Christmas tree, had every imaginable performance mod. Power, brakes, suspension, wheels, CF everything, a small computer inside for on the spot tuning etc.

When you get to that level, I guess the only other thing left to do is an $8000 wing.

Not really sure how much driver mod he had though...

haha if you spend $100k on a racecar you should know how to drive. I'd be embarrassed to have that thing and get passed by a normal track car.

@bigjae: I like getting passed by cars that are amazing enough to distract me. Last one to do that was a Ferrari 430 challenge in the chicane at Barber. I stared at it for way too long.